Chemistry Unit 1 Exam

Which of the following would be considered a PURE SUBSTANCE? (Choose all that apply)

• Oxygen (O)

• Salt Water (NaCl + H2O)

• Carbon Dioxide (CO2)

• Water (H2O)

• The Atmosphere

Which statement best describes the liquid and gas states?

• both take the shape of their container and only liquids expand to fill the volume of their container

• both take on the shape of their container and only gases fill the volume of their container

• both expand to fill the volume of their container and only gases take on the shape of their container

• both expand to fill the volume of their container and only liquids take on the shape of their container

True or False?
Some examples of a chemical change are bubbling,color change, and fizzing.

• True
• False

which is an example of a physical change?

• wood burning
• ice melting
• water dissolving
• paper burning

Which of the following defines a compound?                                                                                            

• 1 element
• 2 or more elements joined by a chemical bond
• smallest defined unit of matter
• particle

What is a significant figure?

• Numbers that are reliable, necessary, and precise.

• The number with the most digits.

• The number with the least digits.

• The number with the least amount of zeros.

ALL non-zero digits are ALWAYS significant!

• True

• False

ALL zero’s in-between non-zero digits are NEVER significant

• True

• False

Zero’s at the end of a number WITH at decimal point ARE NOT significant

• True

• False

Zero’s at the end of a number WITH a decimal point ARE significant

• True

• False